Nozzle construction



March 2,1965

Filed Feb. 16, 1962 FIG! 29 FIG 5 J. F. CAMPBELL NOZZLE CONSTRUCTION 2 Sheets-Sheet 1 I mmvmx. JOHN E CAMPBELL ATTORNEYS March 1965 J. F- CAMPBELL 3,

NOZZLE CONSTRUCTION Filed Feb. 16, 1962 2 Sheets-Sheet 2 lol 93 FIG 8 MAXIMUM 66 PSRESSURE NOZZLE PRESSURE DROP FIG 9 INVENTOR. l JOHN F. CAMPBELL BY MINIMUM I 1 1 I 1 l 1 1| m. 90m- FLOW I 5 3 FUEL FLOW A'ITORNEYS United States Patent 3,171,601 NOZZLE CGNSTRUCTION John F. Campbell, Beech Knoll, Timberidge Trail, Gates Mills, Ohio Filed Feb. 16, 1962,, Ser. No. 174,371 11 (Ilaims. ((Zl. 239-453) This invention relates as indicated to a novel nozzle construction and, more particularly, to a spray nozzle especially adapted for the injection of liquid fuels into the combustion chambers of various types of engines. This application represents a continuation-in-part of my cope-nding application Serial No. 43,767, filed July 19, 1960, for Nozzle Construction, now Patent No. 3,057,560.

In my U.S. Patent 2,801,881, granted August 6, 1957, and in such U.S. application Serial No. 43,767, filed July 19, 1960, now Patent No. 3,057,560, I disclose nozzle constructions suitable for use in gas turbine and ram-jet engines which, at the present time, are chiefly employed in aircraft and air-borne missiles. The operation of high speed air-borne vehicles is now such that it is not uncommon for the temperature of the fuel in the nozzle to reach values approaching 700 F. Fuels used at present boil at this temperature unless kept at pressures of about 10 atmospheres (about 150 p.s.i.) or more. Boiling of these fuels within the nozzles can be extremely detrimental to the operation thereof since it increases the formation of sludge, varnish and solids. Such formations can cause malfunctioning of the entire fuel system.

It is therefore an object of this invention to provide an improved nozzle construction.

Another object is to provide such a nozzle for the spraying of liquid fuels into a combustion chamber adapted to operate at elevated temperatures.

A further object is to provide such a nozzle wherein the liquid fuel is prevented from boiling prior to passing the discharge end of the nozzle.

Yet another object is to provide such a nozzle which produces a finely atomized spray at a short distance therefrom, e.g., two inches from the nozzle.

A still further object is to provide such a nozzle wherein the liquid fuel is maintained under a relatively high pressure (e.g., about 150 p.s.i.) until released through the discharge orifice of the nozzle.

Other objects and advantages of the present invention will become apparent as the following description proceeds.

To the accomplishment of the foregoing and related ends, the invention, then, comprises the features hereinafter fully described and particularly pointed out in the claims, the following description and the annexed drawings setting forth in detail certain illustrative embodiments of the invention, these being indicative, however, of but a few of the various ways in which the principle of the invention may be employed.

In said annexed drawings:

FIG. 1 is a longitudinal section through a nozzle embodying the principles of my invention;

FIG. 2 is an elevation view of the pintle valve assembly of FIG. 1;

FIG. 3 is an end view of the valve assembly as viewed from the left side of FIG. 2;

FIG. 4 is a fragmentary longitudinal section corresponding to FIG. 1 but showing an alternative embodimerit of the valve assembly;

FIG. 5 is a fragmentary longitudinal section corresponding to FIG. 1 but showing a dual-orifice type nozzle;

FIGS. 6 and 7 are enlarged fragmentary cross-sectional views of an assembly similar to that shown in FiG. 1, showing further modifications of the present invention;

FIG. 8 is a longitudinal section of a further alternative embodiment of the present invention; and

FIG. 9 is a plot of various flow-pressure relationships obtainable with the present invention.

Two of the more important features of the instant invent-ion are the provision of a special form of variable area exit valve of the pintle or poppet type, and, the means for varying axially the location of the pintle valve head with respect to the swirl chamber inlet valve. Since this invention is an improvement on my nozzles described in my U.S. Patent 2,801,881 and my U.S. application Serial No. 43,767, now Patent No. 3,057,560, mentioned above, all of the meritorious features of those nozzles are achieved in addition to those peculiar to the instant invention.

Referring now to FIGS. 1, 2 and 3, the embodiment of my invention there illustrated comprises an outer body portion 1 adapted to be connected with an appropriate manifold for delivery of fuel to its open end 2. A restricted axially disposed exit orifice 3 is provided near the other end of the body portion opening into a divergent cone 4. The body portion has a cylindrical inner bore 5 coaxial with the exit orifice 3 within which valve 6 is adapted to be fitted for axial reciprocation. The bore 5 opens into a swirl chamber 7 of larger diameter whose upper tapered conical surfaces 8 and 9 slope toward the exit orifice 3. Valve member 6 is of generally cylindrical form but has an upper portion 19 containing helical grooves 11 of uniform disposition and cross section except in their end portions 12 approaching the swirl chamber '7. These end portions 12 gradually taper in width and in depth and finally terminate a short distance from the annular upper end 10 of valve member 6. Valve member 6 has an annular circumferential groove 13 therein separating its upper portion 10 from its lower portion 14. The lower portion 14 comprises lands 15 separated by wide scallops or grooves 16 which extend longitudinally from the annular groove 13 to the open end 2 of the body portion 1. Thus, the fuel enters the open end 2, flows through the scallops 16 into the annular groove or chamber 13 and through the helical grooves 11 into the swirl chamber 7 and thence out through exit orifice 3 and divergent cone 4.

The valve member 6 has a pintle shaft 17 extending axially therethrough which terminates in a pintle or poppet valve head 18 located within the divergent cone 4-. The bottom surface 19 of the pintle head is a frustum of a cone, the apex angle of which is greater than the apex angle of the divergent cone 4.

A straight slender spring wire member 20 is secured to the pintle shaft 17, as by welding to shouldered portion 21 of the pintle shaft 17. The pintle shaft 17 is secured in valve member 6 as by means of a resilient spring clip 23 which is yieldably engaged between the shouldered portion 21 and the bottom end 24 of valve member 6. The upper end of pintle shaft 17 which protrudes beyond the upper end of valve member 6 is equipped with a shoulder 25, and a shim 26 of desired thickness is provided to axially locate the pintle head 18 with respect to the upper end 10 of valve member 6. By the selection of shims 26 of different thicknesses, the axial relationship between the pintle head 18 and the valve member 6 may be varied. The importance of this relationship will ap pear hereinafter.

A preloaded compression spring 27 is coaxially seat-ed within the inlet end 2 of the body portion 1 and bears against a shim 28 mounted on the movable seating member 29. The latter member is provided with a central opening and conical seat 30 adapted to support ball 31 which is attached to the bottom end of spring wire member 20. The seat 30 is slotted at 32 so that the ball 31 may pass through the opening 33 when it is desired to assemble or disassemble the component parts. The spring 27 may be a multi-coil spring machined from bar stock as shown and described in my U.S. Patent 2,749,182.

It will be obvious therefore from the foregoing description that the spring 27 will tend to hold the pintle head 18 seated within the divergent cone 4. The outer peripheral edge 34 of the pintle head 18 will engage the surface of the divergent cone 4 in such a manner as to prevent fuel from emanating from the nozzle. Dependmg upon the axial relationship between the pintle head 18 and the valve member 6 as determined by shim 26, the end portions 12 of the helical grooves 11 in the valve member 6 will protrude to a greater or lesser extent into the bottom of the swirl chamber 7 while the pintle head 18 is seated within the divergent cone 4. This in turn will provide a varying amount of area exposed by the grooves 12 into the swirl chamber. As stated before, this can be controlled by the thickness of the shim 26. The inlet fuel pressure will cause fuel to flow through the grooves 11 and 12 into the swirl chamber 7. When a sufiicient pressure is built up within the exit orifice 3 and acting on the under surface 19 of the pintle head 18, the pintle head 18 will be forced upward permitting the fuel to discharge out along the surface of the divergent cone 4. Such an arrangement ensures that the fuel will be kept under a preselected pressure (e.g., 150 psi.) until it actually emanates from the nozzle. The area of the grooves 12 exposed within the swirl chamber 7, the dimensions of the swirl chamber 7, and the rate or characteristics of the spring 27 are all interrelated and act to determine the pressure of the fuel within the exit orifice 3 prior to its release from the nozzle. For any appropriately selected values of spring rate, swirl chamber geometry and pintle head size, there will be only one relationship between the exposed area of the helical grooves 12 within the swirl chamber 7 and the pintle opening (which is the area between the circumferential edge 34 on the pintle head 18 and the adjacent interior surface of the divergent cone 4). The design should be such that the pintle head 18 will open promptly enough in response to a fluid pressure increase to obtain at least a 0.0007 inch clearance in the pintle opening 35. This will ordinarily produce a liquid film of sufiicient thickness to maintain continuity 4 of the film at a fairly low flow rate as may be required.

Referring now to FIG. 4, the valve member 6 is shown to contain a plurality of orifices 40 communicating with the annular chamber 13. In addition, the pintle shaft 41 is so constructed within the valve member 6 that an annular chamber 42 is provided in communication with the pintle shaft 41 above the groove 42 is provided with fixed area primary swirl slots 43 communicating with the groove 42 and the swirl chamber 7. Although this particular structure does not utilize the shim 26 shown in FIG. 1-, the pintle shaft '41 may be otherwise axially adjusted with respect to valve member 6. It can'be seen from this structure that fuel will flow from annular chamber 13 throughopenings 4i) and annular groove 42, through the fixed area primary openings 40. Further,

pressure increases, the valve member'6 will move upwardly progressively to uncover the slots 12 for progressively increased fiow through the increasing gap 35 between the pintle head 18 and divergent cone 4.

FIG. 5 illustrates an embodiment of this invention somewhat modified from that shown in FIGS. 1 and 4 in that a primary fuel system is provided independent of that described with reference to FIG. 1. In FIG. 5, the pintle head 44 has a primary discharge orifice 45 which terminates in a divergent cone 46. Upstream of the primary orifice 45 is a primary swirl chamber 47 and helical primary swirl slots 48 communicating with chamber 13 via radial passages 40 and 49 and chamber 42. Pintle shaft 50 extends into the bore of the sleeve portion 51 and is fixedly attached thereto, for example by welding at 52; In this embodiment, fuel may flow through the annular chamber 13, registered openings 40 and 49, an- :uular groove 42 fixed area helical primary swirl slots 45,

swirl slots 43 and into the swirl chamber 7. As the inlet inner swirl chamber 47, and out through inner exit orifice 45 and inner divergent cone 46. The secondary circuit is like FIG. 1 whereby as the, pintle 44 moves away from its seat there will be a prescribed pressure drop to preclude boiling of the fuel in the nozzle.

in FIGS. 6 and 7, variations are shown in the construction of the walls (surfaces and 61) of swirl chamber 7. In FIG. 7, surface 60 is shown to have a divergent or outward taper; in FIG. 6, surface 61 is shown to have a convergent or inward taper. These variations will affect the pressure drop from the helical grooves 11 to the swirl chamber 7 which will in turn affect the slope of the plotted curve of fuel flow versus fuel pressure. These relationships are discussed in detail in my aforementioned copending application, Serial No. 43,767, filed July 19, 1960, now Patent No. 3,057,560. Thus in both the FIGS. 6 and 7 embodiments a variable restriction is provided between the annular upper end 63 of the upper portion 10 of the valve member 6 and swirl chamber 7 decreasing with valve movement in FIG. 6 and increasing with'such movement in FIG. 7. With reference to FIG. 9, the curve as represents generally the flow versus pressure characteristics which it may be desired to obtain. The curve 66 represents the typical flow versus pressure characteristics of a nozzle construction in accordance with thatshown in my aforementioned copending application. By tapering in the wall surface as shown at 61 in FIG. 6, the terminal portion of the resulting curve is brought nearer the curve 65, or by tapering out the wall surface as shown at as in FIG. 7, the terminal portion of the curve is brought higher or nearer curve 66.

Referring now to the embodiment of the invention illustrated in FIG. 8, the outer body portion 70 is provided with an annular extension 71 properly to be mounted in an engine or like housing. The valve body 72 extends longi-.

tudinally within the body 70 through bore 73 and is provided with the scallops or grooves 74 leading into an annular groove 75 which is larger at its circumferential outer extent due to the wall 76 being inclined as shown. The groove 75 corresponds to the groove 13 in the FIG. 1 embodiment. The upper'portion of the valve member beyond the groove 75 is provided with helical grooves 77 of uniform disposition and cross section with the exception that their end portions 78 gradually taper in width and depth and finally terminate a'short distance from the annular upper end 79 of the valve member. A uniform circumferentially annular groove 80 is superimposed on the helical grooves 77 and serves to increase the opening between such grooves and the swirl chamber 81 as the valve member 72 moves axially against the pressure of spring 82. Thus as the pressure increases and the valve member '72 moves axially upwardly, the groove Stl'will be exposed to the swirl chamber wall 83 and the spin velocity of the fluid will be somewhat dissipated.

The valve member 72 also has a pintle shaft 85 extending therethrough with shim 86 disposed between the upper end 79 of the valve body and shoulder 87 on such pintle shaft. The upstream end of'the valve body is provided with an annular recess 90 housing a spring 91 which extends between the bottom of the recess and washer 92 bear-ing against shoulder 93 on the pintle shaft. A bathe member 94 is secured within such recess and extends substantially to cover the entry end of the scallops or grooves 74 to provide a restriction which will move with the valve body. Thus the major force on the valve member against the pressure of spring 82 will be exerted on the relatively large exposed area of the member 94. The primary pressure drop is then at the member 94. As noted at 95, the

wall of the bore 73 may be tapered slightly to provide a.

variable constriction between the baffle member 94 and the wall of the bore 73; In the illustrated embodiment, the wall is shown as tapered inwardly so that as the valve member moves against the pressure of spring 82, the constriction between the bathe and the wall of the bore 73 will enlarge. As in the case of the embodiment illustrated in FIGS. 6 and 7, it will be understood that the bore wall may be tapered in the opposite direction to achieve a decreasing annular constriction area as the valve member moves against the pressure of spring 82. In this manner the variations in the annular constriction will aifect the pressure drop and the relationships of the fuel flow and pressure much in the same manner as disclosed in such FIGS. 6 and '7. The valve member 72 in this embodiment is also more resiliently held against the shim 86 than in the FIG. 1 embodiment. The pintle shaft may be secured to a spring retainer 97 provided with a shoulder 98 accommodating a shim 99 supporting one end of the spring 82. The other end of the spring may be secured on the shoulder 104) of retainer 101 secured to the valve body 70.

Although the valve member as described herein has its helical grooves contained only in its top portion, a valve member having helical grooves for its entire length such as shown in FIG. 2 of my US. Patent 2,801,881 may be substituted therefor. Further, any suitable resilient means may be substituted for the spring 27 shown in FIG. 1.

This invention has been advantageous in providing a new nozzle construction capable of fine atomization with short penetration, low supply line pressure at rated flow, uniformity of composition of spray cone as well as an ability to perform well on high viscosity or contaminated fuels. In any event, the pressure drops in the nozzles herein are such as to prevent fuel boiling at any zone upstream of the exit orifices.

Other modes of applying the principle of the invention may be employed, change being made as regards the details described, provided the features stated in any of the following claims or the equivalent of such be employed.

1, therefore, particularly point out and distinctly claim as my invention:

1. A nozzle having a body portion with a bore therein, said bore having an inlet end, an exit orifice near the discharge end coaxial with said bore, a swirl chamber upstream of said orifice and communicating with said bore, a cylindrical valve member fitted within said body portion for reciprocation therein, one end of said valve member protruding into said swirl chamber, a plurality of similar uniformly arranged helical grooves in the outer surface of said valve member communicating with the inlet end of said bore, said grooves tapering toward said swirl chamber in their adjacent end portions, a pintle shaft extending coaxially from said valve member through said exit orifice, a pintle head downstream of said swirl chamber on said pintle shaft of slightly greater diameter than said exit orifice, said exit orifice being upstream of said pintle head and opening into a divergent cone in said discharge end of said bore surrounding said pintle head, resilient means biasing said valve member and pintle head in an axial direction tending to seat the latter against the inner surface of said divergent cone, said helical slots in said valve member communicating said inlet end of said bore with said swirl chamber when said pintle head is in such seated position, the diameter of said pintle shaft being substantially less than the diameter of the exit orifice and the swirl chamber thereby to expose a substantial area of said pintle head to said exit orifice, and means to hold said pintle head in predetermined axially spaced relation to said valve member thus to vary the extent to which said helical slots extend into said swirl chamber when said pintle head is in such seated position.

2. The nozzle according to claim 1, wherein the axially inner surface of said pintle head is a frustum of a cone, the apex angle of which is greater than the apex angle of the said divergent cone.

3. The nozzle according to claim 1 including an annular groove superimposed on said plurality of uniformly arranged helical grooves between the ends thereof.

4. The nozzle according to claim 1 including a battle member secured to said valve member upstream of said helical grooves against which fluid passing into said inlet end acts to move said valve member against the bias of said resilient means.

5. The nozzle according to claim 1, wherein said lastmentioned means includes a replaceable shim interposed between said pintle shaft and valve member.

6. The nozzle according to claim 1, including an inner annular chamber Within said shaft, radial passages leading from each of said helical grooves to said inner annular chamber at circumferentially spaced points equidistant from the end of said valve member, swirl slots leading from said inner annular chamber to an inner swirl chamber within said shaft, a passage leading from said inner swirl chamber through said pintle head to a coaxial orifice in the end of said pintle head, said bore exit orifice opening into a divergent cone in said discharge end of said bore surrounding said pintle head, and resilient means biased normally to hold said pintle head against the inner surface of said divergent cone so that fluid flow may be only through said orifice in said pintle head until inlet pressure rises to a figure sufficient to unseat said pintle head from said divergent cone.

7. The nozzle according to claim 1, wherein said pintle shaft and pintle head are of a solid construction.

8. The nozzle according to claim 1, wherein said pintle head has a bottom surface, the length of which is substantially less than the length of said divergent cone.

9. The nozzle according to claim 5, having means disposed between said pintle shaft and valve member resiliently to hold said valve member against said shim.

10. In a nozzle having a fluid inlet end, an exit orifice end, a fiow passage extending therebetween and means defining a spin chamber upstream of said orifice end, a spring closed, fluid pressure actuated valve member mounted for movement in said nozzle to open and close fluid communication through said nozzle, said valve memher having opposite sides thereof exposed to fluid under pressure in said inlet end and such spin chamber and being formed with generally helical slots through which fluid flows from said inlet end into such spin chamber when said valve member is in open position; and means at the inlet end of said valve member operative to provide a variable constriction for the passage of fluid into said inlet end according to the extent of movement of said valve member to open position.

11. The nozzle according to claim 10, wherein said last-mentioned means includes a baffle member secured to said valve member in the fiow passage of said nozzle varying in cross-section area according to the extent of movement of said valve member to open position as aforesaid.

References Cited in the file of this patent UNITED STATES PATENTS 2,656,218 Campbell Oct. 20, 1953 2,749,182 Campbell June 5, 1956 2,801,881 Campbell Aug. 6, 1957 3,057,560 Campbell Oct. 9, 1962 

10. IN A NOZZLE HAVING A FLUID INLET END, AN EXIT ORIFICE END, A FLOW PASSAGE EXTENDING THEREBETWEEN AND MEANS DEFINING A SPIN CHAMBER UPSTREAM OF SAID ORIFICE END, A SPRING CLOSED, FLUID PRESSURE ACTUATED VALVE MEMBER MOUNTED FOR MOVEMENT IN SAID NOZZLE TO OPEN AND CLOSE FLUID COMMUNICATION THROUGH SAID NOZZLE, SAID VALVE MEMBER HAVING OPPOSITE SIDES THEREOF EXPOSED TO FLUID UNDER PRESSURE IN SAID INLET END AND SUCH SPIN CHAMBER AND BEING FORMED WITH GENERALLY HELICAL SLOTS THROUGH WHICH FLUID FLOWS FROM SAID INLET END INTO SUCH SPIN CHAMBER WHEN SAID VALVE MEMBER IS IN OPEN POSITION; AND MEANS AT THE INLET END OF SAID VALVE MEMBER OPERATIVE TO PROVIDE A VARIABLE CONSTRICTION FOR THE PASSAGE OF FLUID INTO SAID INLET END ACCORDING TO THE EXTENT OF MOVEMENT OF SAID VALVE MEMBER TO OPEN POSITION. 